CVE-2026-62289Network attack vector

Crash or corrupt tiling via double clap transform

Published Aug 18, 2026 · Updated Aug 19, 2026

Integer underflow in libheif before 1.23.1 allows attackers to crash applications or corrupt tiling results via crafted HEIF or AVIF files. When heif_image_handle_get_image_tiling(handle, 1, &tiling) runs, ImageItem::get_heif_image_tiling() returns clean-aperture-transformed dimensions and process_image_transformations_on_tiling() applies the clap transform again, passing zero to Box_clap::left_rounded(0) and underflowing image_width - 1 into Fraction(0xFFFFFFFF, 2). Reachability requires an application to process an attacker-supplied file and call the tiling API with transformations enabled; debug builds abort on an assertion, while release builds can return a corrupt crop and zero-width tiling metadata.

CVSS severity4.3
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in libheif before 1.23.1 allows attackers to crash applications or corrupt tiling results via crafted HEIF or AVIF files. When heif_image_handle_get_image_tiling(handle, 1, &tiling) runs, ImageItem::get_heif_image_tiling() returns clean-aperture-transformed dimensions and process_image_transformations_on_tiling() applies the clap transform again, passing zero to Box_clap::left_rounded(0) and underflowing image_width - 1 into Fraction(0xFFFFFFFF, 2). Reachability requires an application to process an attacker-supplied file and call the tiling API with transformations enabled; debug builds abort on an assertion, while release builds can return a corrupt crop and zero-width tiling metadata.

The record

CVE
CVE-2026-62289
Published
Aug 18, 2026
Updated
Aug 19, 2026
Vendor
Struktur AG
Product
libheif
Classifications
CWE-191, CWE-617
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.23.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Struktur AG · libheifversion=< 1.23.1

Published CVSS scores

4.3GitHub CNA via NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
6.5GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
7.5GitHub Security Advisory (server-side)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
CWE-617Reachable Assertion

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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